Buggy code:
public abstract class AbstractJDBCTestElement extends AbstractTestElement implements TestStateListener { private static final long serialVersionUID = 235L ; private static final Logger log = LoggingManager . getLoggerForClass ( ) ; private static final String COMMA = "," ; private static final char COMMA_CHAR = ',' ; private static final String UNDERSCORE = "_" ; private static final String NULL_MARKER = JMeterUtils . getPropDefault ( "jdbcsampler.nullmarker" , "]NULL[" ) ; private static final String INOUT = "INOUT" ; private static final String OUT = "OUT" ; protected static final String ENCODING = "UTF-8" ; private static final Map < String , Integer > mapJdbcNameToInt ; static final String SELECT = "Select<seq2seq4repair_space>Statement" ; static final String UPDATE = "Update<seq2seq4repair_space>Statement" ; static final String CALLABLE = "Callable<seq2seq4repair_space>Statement" ; static final String PREPARED_SELECT = "Prepared<seq2seq4repair_space>Select<seq2seq4repair_space>Statement" ; static final String PREPARED_UPDATE = "Prepared<seq2seq4repair_space>Update<seq2seq4repair_space>Statement" ; static final String COMMIT = "Commit" ; static final String ROLLBACK = "Rollback" ; static final String AUTOCOMMIT_FALSE = "AutoCommit(false)" ; static final String AUTOCOMMIT_TRUE = "AutoCommit(true)" ; private String query = "" ; private String dataSource = "" ; private String queryType = AbstractJDBCTestElement . SELECT ; private String queryArguments = "" ; private String queryArgumentsTypes = "" ; private String variableNames = "" ; private String resultVariable = "" ; private String queryTimeout = "" ; private static final Map < Connection , Map < String , PreparedStatement > > perConnCache = new ConcurrentHashMap < Connection , Map < String , PreparedStatement > > ( ) ; protected AbstractJDBCTestElement ( ) { } protected byte [ ] execute ( Connection conn ) throws IOException , UnsupportedEncodingException , UnsupportedOperationException , SQLException { } private String resultSetsToString ( PreparedStatement pstmt , boolean result , int [ ] out ) throws UnsupportedEncodingException , SQLException { } private int [ ] setArguments ( PreparedStatement pstmt ) throws IOException , SQLException { } private static int getJdbcType ( String jdbcType ) throws SQLException { } private CallableStatement getCallableStatement ( Connection conn ) throws SQLException { } private PreparedStatement getPreparedStatement ( Connection conn ) throws SQLException { } private PreparedStatement getPreparedStatement ( Connection conn , boolean callable ) throws SQLException { } private static void closeAllStatements ( Collection < PreparedStatement > collection ) { } private String getStringFromResultSet ( ResultSet rs ) throws UnsupportedEncodingException , SQLException { } public static void close ( Connection c ) { } public static void close ( Statement s ) { } public static void close ( ResultSet rs ) { } public int getIntegerQueryTimeout ( ) { int timeout = 0 ; try { <START_BUG> if ( StringUtils . isNumeric ( query ) ) { <END_BUG> timeout = Integer . parseInt ( queryTimeout ) ; } } catch ( NumberFormatException nfe ) { timeout = 0 ; } return timeout ; } public String getQueryTimeout ( ) { } public void setQueryTimeout ( String queryTimeout ) { } public String getQuery ( ) { } @ Override public String toString ( ) { } public void setQuery ( String query ) { } public String getDataSource ( ) { } public void setDataSource ( String dataSource ) { } public String getQueryType ( ) { } public void setQueryType ( String queryType ) { } public String getQueryArguments ( ) { } public void setQueryArguments ( String queryArguments ) { } public String getQueryArgumentsTypes ( ) { } public void setQueryArgumentsTypes ( String queryArgumentsType ) { } public String getVariableNames ( ) { } public void setVariableNames ( String variableNames ) { } public String getResultVariable ( ) { } public void setResultVariable ( String resultVariable ) { } @ Override public void testStarted ( ) { } @ Override public void testStarted ( String host ) { } @ Override public void testEnded ( ) { } @ Override public void testEnded ( String host ) { } private static final void cleanCache ( ) { } }

Fix:
if ( StringUtils . isNumeric ( queryTimeout ) ) {